Variable-pressure casing and method of using for therapeutic purposes



July 9. 1968 FIG. I

T. E. SPIELBERG VARIABLE-PRESSURE CASING AND METHOD OF FOR THERAPEUTIC PURPOSES USING Filed Dec. 1965 F BS0150 OOOO JOOOO elm INVENTOR. THEODORE E. SPIELBERG,M.D.

2 7 @WWZ) TTORNEYS United States Patent 3,391,692 VARIABLE-PRESSURE CASING AND METHOD OF USING FOR THERAPEUTIC PURPOSES Theodore E. Spielberg, 126 Babcock St., Brookline, Mass. 02146 Filed Dec. 23, 1965, Ser. No. 516,164 Claims. (Cl. 128--24) ABSTRACT OF THE DISCLOSURE An inflatable casing is secured around a limb most tightly around the lower portions of the limb and increasingly loosely around the upper portions of the limb to provide a longitudinal pressure gradient along the limb when the casing is cyclically inflated and deflated. This gradient assists in providing a unidirectional flow of blood toward the heart and prevents blood from pooling in the extremities. The casing may take the form of a flat, approximately rectangular bag which is wrapped around the limb by means of straps whose length is adjustable to provide a range of pressure gradients or it may take the form of an approximately conical bag contoured to fit the limb most tightly at the lower portion of the limb and more loosely along the upper portion of the limb to provide a predetermined pressure gradient for a given inflation level.

My invention relates to apparatus for treatment of diseases of the circulatory system. In particular, it relates to apparatus for promoting a unidirectional flow of body fluid within a portion of an animal body whereby the formation of venous thrombi may be prevented.

Recent investigations into the treatment of pulmonary embolic disease have revealed that pulmonary embolism is a major cause of death, especially among patients confined to extended bed-rest. The formation of these embolisms has been attributed to conditions of stasis or low velocity blood flow such as occurs in the veins. The prob lem is especially acute in the distal portions of the body and, in particular, in the lower limbs of patients confined to extended bed-rest.

Various attempts have been made to develop devices to assist the flow of blood in arteries and veins and to assist in treatment of diseases of the circulatory system. The construction of these devices, however, was often such as to require special care in their application to the limbs of the body or to cause physical discomfort to the patient when in use. In addition, certain of these devices were relatively ineflicient and were required to be specially fitted to the limb to be treated. I have found that by completely enclosing the limb being treated within an inflatable casing or cuff which is adapted to provide varying pressures on the limb along the length thereof, an eificient means of promoting a unidirectional flow of blood within the veins from the extremities toward the heart is achieved with minimum physical discomfort to the patient.

Accordingly, it is an object of my invention to provide apparatus for treatment of diseases of the circulatory system which may readily be applied to a wide variety of limbs of different shapes and sizes and which causes little or no physical discomfort to the patient being treated. A feature of one embodiment of my invention reside in the provision of adjustable securing means which allows the physician or other person applying the apparatus to the limb under treatment to adjust the pressure along various portions of the limb to suit the physical charac- 3,391,692 Patented July 9, 1968 ice teristics and requirements of the particular patient being treated.

Other and further objects and features of my invention appear below in the following detailed description of a preferred embodiment thereof which has been selected for purposes of illustration and which is shown in the accompanying drawings in which:

FIGURE 1 is a plan view of one embodiment of my invention showing an inflatable casing having adjustable securing means;

FIGURE 2 is a cross sectional view of my invention taken along the lines 2-2 or FIGURE 1;

FIGURE 3 is a pictorial view of the device of FIGURE 1 as applied to a limb under treatment; and

FIGURE 4 is a pictorial view of an alternative form of my invention shown as applied to a limb under treatment.

In accordance with my invention, I provide an inflatable casing or pressure cutf having a valve attached thereto for the admission and discharge of fluid whereby a pressure gradient may cyclically be applied to the limb under treatment. In addition, I provide a fluid cycling system attached to the valve, the cycling system including a source of pressurized fluid, a pressure regulator valve, and a cycle control system including a. valve and timer unit. In one embodiment of my invention the inflatable casing is secured to the limb to be treated by means of a plurality of adjustable straps which allow the generation of any desired distribution of pressure along the length of the limb. In another embodiment of my invention I provide an inflatable casing which is contoured to the limb to be treated and which establishe a single preselected pressure gradient along the length of the limb.

FIGURES 1 and 2 show an inflatable: casing 10 having a pair of walls 12 and 14 respectively formed of rubber, plastic, or other resilient material and shaped in the form of a rectangular bag which is sealed completely around all edges 16. An orifice 18 which communicates with the interior of the casing 10 is provided in one of the side walls of the casing and is connected to a conduit 20 of rubber, plastic or similar material whereby fluid may be admitted to, and discharged from, the interior of the casing. Attached to one of the edges 16 are a plurality of straps 22 of progressively increasing length and having female fasteners 23a positioned on the lower side of the straps 22 which cooperate with male fasteners 23b positioned on the upper wall 12 of the casing 10. The width of the straps 22 is preferably of the order of three inches, although the width and number of straps may be varied in accordance with the width of the casing 10 and with the pressure distribution which it is desired to attain. A number of fasteners 23b are provided in order to allow the casing to be secured to the limb of the patient with varying degrees of pressure along the length of the casing.

FIGURE 3 shows the casing 10 secured to the leg of a patient under treatment. In order to secure the desired pressure gradient along the length of the limb, the straps 22 are wrapped most tightly around the lower portion of the limb and are thence wrapped with decreasing tension around the successive upper portions of the limb such that the uppermost portion of the limb has the least tension. The conduit 20 is then connected to the gate valve 24 which has fluid inlet port 26, fluid supply port 28, and fluid exhaust port 30. Connected to the gate valve 24 by means of conduit 20 is pressure regulating valve 32 which regulates the pressure supplied via conduit 34 from a source of pressurized fluid (not shown); illustratively in FIGURE 3, the fluid is air. The pressurized fluid supply may be obtained from any of a number of well known sources such as bottled air or gas or by means of compessor motors operating on a fluid reservoir. Systems for supplying fluid under pressure are well known in the art and accordingly will not be described in further detail.

Attached to the valve 24 is a rocker arm 36 which controls the admission and discharge of fluid to and from the casing 10. The rocker arm 36 is connected to a cycle-timer 38 which may be adjusted to provide any desired pressure cycle for the casing 16 and which may alternately inflate and deflate the casing by first connecting the inlet port 26 and the supply port 28 to the conduits 34 and 20 respectively and then deflating the casing by connecting the exhaust port 30 to the conduit 20 and allowing the fluid to be discharged from the casing into the atmosphere or other reservoir by means of the port 26. The cycle timer 38 may comprise any of a number of well known systems for providing a timed mechanical displacement and may include, for example, one or more electromagnetic relays actuated from a source of timecontrolled electrical pulses.

As previously mentioned, a pressure gradient is created along the length of the limb by wrapping the straps 22 most tightly along the lower portion of the limb and then with successively decreasing tension along the upper portions of the limb. As the casing 10 is alternately inflated and deflated, the pressure gradient is alternately increased and decreased, thereby applying a pumping action to the limb to force the venous blood toward the heart.

The casing shown in FIGURE 3 allows the pressure gradient to be selected by the physician or other person applying the casing to the limb of the patient. Thus, in applying the casing, allowance may be made for the age of the patient, his weight, the proximity of the patients veins to the surface of the limb being treated, and other conditions peculiar to the particular patient. FIGURE 4 illustrates a contoured form of easing which may be rapidly applied to the limb under treatment but in which the pressure gradient is relatively fixed. The casing 40 is supplied as a single-unit inflatable cell with a slide fastener 42 to secure the opposing ends of the casing. Of course, other types of fasteners may be used if de sired. The casing is supplied in a wide variety of sizes to accommodate itself to the particular limb being treated and is formed in approximately a conical shape so that it may be fitted most firmly around the lower portion of the limb and thence with decreasing tension around the upper portions of the limb. Fitting the casing to the limb in this fashion creates a pressure gradient along the length of the limb when the casing is inflated. This gradient forces the venous blood toward the heart, thus alleviating the stasis conditions which contribute to the formation of the venous thrombi.

From the above it may be seen that I have provided a simple yet efiicient device for promoting a unidirectional flow of body fluid within the portion of an animal body by means of the creation of a pressure gradient operating on the limb to which the device is applied. Further, in one embodiment of my invention, I have provided a device in which the pressure gradient may be adjusted within broad limits by the physician or other person applying the device to the limb under treatment.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efliciently attained and, since certain changes may be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

Having described my invention, I claim:

1. Apparatus for promoting a unidirectional flow of body fluid within a limb of an animal body, comprising, in combination, a single celled cuff of inflatable material adapted to be wrapped substantially completely around said limb and having fluid orifice means attached thereto for connecting the interior of the cuff to a source of pressurized fluid, securing means for securing the cuff to the limb along a longitudinal dimension thereof and adapted to secure the limb more firmly at the distal end thereof than at the proximal end whereby a pressure gradient may be established along the longitudinal length of said limb in such a direction as to urge said blood, when said cuff is alternately inflated and deflated in a cyclical manner, from the distal end of said limb to the proximal end thereof, and means connected to said fluid orifice means for alternately inflating and deflating said cuff to thereby promote a unidirectional flow of body fluid within said limb.

2. The combination defined in claim 1 wherein said means for alternately inflating and deflating said cuff comprises a source of pressurized fluid, valve means for controlling the supply of said fluid to said cuff and the discharging of said fluid from said cuff to a fluid reservoir, and fluid conduit means interconnecting said sourceof pressurized fluid, said valve means, and said fluid orifice means whereby fluid may be supplied to, and removed from, said cuff in a cyclical manner.

3. The combination defined in claim 2 wherein said inflatable cuff is rectangular in shape, said securing means comprising a plurality of straps which are wrapped transversely around said cuff when said cuff is positioned against said limb.

4. The combination defined in claim 2 wherein the inflatable cufl is generally conical in shape, said securing means comprising a plurality of straps adapted to be wrapped transversely around said cuff when said cuff is positioned against said limb.

5. The combination defined in claim 2 wherein said cuff is formed generally in the shape of the limb to which the cuff is to be applied, said cuff being formed with an increasingly greater diameter, proceeding from that portion of the cuff which is to 'be attached to the distal end of said limb to that portion which is to be attached to the proximal end of said limb, than the limb to which it is to be attached.

6. The combination defined in claim 5 wherein said securing means comprises a slide fastener extending longitudinally along said cuff.

7. The method of promoting a unidirectional flow of body fluid within a limb of an animal body comprising the steps of positioning a single-celled cuff of inflatable material substantially completely around said limb, securing the cuff to the limb with a greater circumferential pressure at one end thereof than at the other, and alternately inflating and deflating said cuff to thereby establish a longitudinal pressure gradient along the limb when said cuff is alternately inflated and deflated, said gradient extending in such a direction as to promote a flow of body fluid from that portion of the limb at which the cuff is more firmly secured to that portion of the limb at which it is less firmly secured.

8. The method of claim 7 in which said cuff is secured to said limb with increasing tightness from the proximal portion of said limb to the distal portion thereof, whereby a unidirectional flow of body fluid from the distal portion toward the proximal portion is promoted.

9. The method of claim 8 in which said cuff is inflated and deflated by supplying fluid to, and removing fluid from, said cuff in a cyclical manner.

10. The method of promoting the flow of blood to the heart from distal portions of a limb to thereby preclude the pooling of blood in said portions, comprising the steps of 5 6 (A) positioning an inflatable single-celled cuff around References Cited said limb, (B) securing said cufl. to said limb with increasing UNITED STATES PATENTS tightness from the proximal portions of said limb 2694395 11/1954 Brown to the distal portions thereof, and t 5 2367524 1/1961 chnstflmsen- (C) alternately supplying fluid to, and removing fluid 3153'413 10/1964 G'Ottfned 128*165 from, said cuff in a cyclical manner to thereby es- FOREIGN PATENTS tablish a longitudinal pressure gradient along said 1,291,959 3/1962 France limb while said cuff is being inflated whereby said 5 2 11/1942 Great Britain pressure gradient may promote the flow of blood 10 from said distal portions to said heart. LAWRENCE W. TRAPP, Primary Examiner. 

